// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

#pragma once

#include <memory>
#include <string>
#include <unordered_map>
#include <nebula/future/mutex.h>
#include <aries/parquet/exception.h>
#include <aries/parquet/platform.h>

namespace parquet::encryption {
    /// This class wraps the key access token of a KMS server. If your token changes over
    /// time, you should keep the reference to the KeyAccessToken object and call Refresh()
    /// method every time you have a new token.
    class PARQUET_EXPORT KeyAccessToken {
    public:
        KeyAccessToken() = default;

        explicit KeyAccessToken(const std::string value) : value_(value) {
        }

        void Refresh(const std::string &new_value) {
            auto lock = mutex_.Lock();
            value_ = new_value;
        }

        const std::string &value() const {
            auto lock = mutex_.Lock();
            return value_;
        }

    private:
        std::string value_;
        mutable ::nebula::util::Mutex mutex_;
    };

    struct PARQUET_EXPORT KmsConnectionConfig {
        std::string kms_instance_id;
        std::string kms_instance_url;
        /// If the access token is changed in the future, you should keep a reference to
        /// this object and call Refresh() on it whenever there is a new access token.
        std::shared_ptr<KeyAccessToken> refreshable_key_access_token;
        std::unordered_map<std::string, std::string> custom_kms_conf;

        KmsConnectionConfig();

        const std::string &key_access_token() const {
            if (refreshable_key_access_token == nullptr ||
                refreshable_key_access_token->value().empty()) {
                throw ParquetException("key access token is not set!");
            }
            return refreshable_key_access_token->value();
        }

        void SetDefaultIfEmpty();
    };

    class PARQUET_EXPORT KmsClient {
    public:
        static constexpr const char kKmsInstanceIdDefault[] = "DEFAULT";
        static constexpr const char kKmsInstanceUrlDefault[] = "DEFAULT";
        static constexpr const char kKeyAccessTokenDefault[] = "DEFAULT";

        /// Wraps a key - encrypts it with the master key, encodes the result
        /// and potentially adds a KMS-specific metadata.
        virtual std::string WrapKey(const std::string &key_bytes,
                                    const std::string &master_key_identifier) = 0;

        /// Decrypts (unwraps) a key with the master key.
        virtual std::string UnwrapKey(const std::string &wrapped_key,
                                      const std::string &master_key_identifier) = 0;

        virtual ~KmsClient() {
        }
    };
} // namespace parquet::encryption
